Our research interests lie in the analysis of gene activity, gene amplification, and nucleic acid and protein syntheses in sciarids. Presently our work is devoted largely in DNA synthesis at the molecular and the chromosomal levels. For chromosomal analysis we are using polytene chromosomes of Rhynchosciara, employing the unusual biology of this fly and the fact that hormonal injections into young larvae stimulate simultaneously DNA synthesis in a great number of cells at a precisely defined moment. We are studying the responses of DNA and RNA synthesis to infectious agents which induce great hypertrophy in the polytene chromosomes; we are interested in determining whether these microorganisms, which abolish normal control over polytenization, can alter the normal pattern of DNA synthesis. We have initiated work with screwworm embryos, which undergo cell division at much faster rates than Rhynchosciara or Drosophila, so that we can examine DNA synthesis at the molecular level by submitting early embryos to different temperatures which change the rate of cell division. Thereby we may examine how the rate of cell division affects the number of initiation sites of DNA synthesis in related eukaryotic species. All the research described above is presently in progress and will be continued throughout the next year.